US4040708A - Cathode ray tube base - Google Patents

Cathode ray tube base Download PDF

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Publication number
US4040708A
US4040708A US05/702,096 US70209676A US4040708A US 4040708 A US4040708 A US 4040708A US 70209676 A US70209676 A US 70209676A US 4040708 A US4040708 A US 4040708A
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United States
Prior art keywords
apertures
diameter
tube
peripheral wall
washer
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Expired - Lifetime
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US05/702,096
Inventor
Ralph E. Neuber
Charles H. Rehkopf
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GTE Sylvania Inc
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GTE Sylvania Inc
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Priority to US05/702,096 priority Critical patent/US4040708A/en
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Assigned to NORTH AMERICAN PHILIPS CONSUMER ELECTRONICS CORP. reassignment NORTH AMERICAN PHILIPS CONSUMER ELECTRONICS CORP. ASSIGNS ITS ENTIRE RIGHT TITLE AND INTEREST, UNDER SAID PATENTS AND APPLICATIONS, SUBJECT TO CONDITIONS AND LICENSES EXISTING AS OF JANUARY 21, 1981. (SEE DOCUMENT FOR DETAILS). Assignors: GTE PRODUCTS CORPORATION A DE CORP.
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Expired - Lifetime legal-status Critical Current

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/92Means forming part of the tube for the purpose of providing electrical connection to it

Definitions

  • This invention relates to tube bases and more particularly to tube bases for cathode ray tubes which employ high voltage differentials between various tube pins.
  • cathode ray tubes particularly those employed in color television, have a small diameter neck containing the electron gun or guns.
  • the necessary operating voltages for the various elements of these guns are supplied via tube pins which are sealed into the end of the tube.
  • the neck diameter has gotten smaller, decreasing from 36 mm to 29 mm, it has dictated that the tube pins, which are annularly arrayed thereabout, keep getting closer together.
  • Yet another object of the invention is to prevent or alleviate inter-pin arcing in cathode ray tubes.
  • Yet another object of the invention is the provision of a tube base which includes arcing protection.
  • a base for a cathode ray tube which includes an electrically insulating washer confined within a walled rim of a plastic base. Provision is made therein for the projection therethrough of the tube pins. The compressible washer fills the voids between tube pins at the glass-base interface and provides an effective arcing deterent.
  • FIG. 1 is an exploded perspective view of a base in accordance with an embodiment of the invention.
  • FIG. 2 is an elevational view of a base and CRT neck, with some parts in section.
  • FIG. 1 a base 10 for a cathode ray tube 12.
  • the base 10 comprises a circular rim 14 surrounded by a circumferential wall 15 having an outer diameter A and an inner diameter B.
  • a plurality of tube pin receiving apertures 16 extend through the rim 14 and are spaced inwardly from the inner circumference of wall 15 in an annular array.
  • a hollow, substantially centrally located crown 18 is positioned on rim 14 and extends rearwardly therefrom, the internal portion 20 thereof being adapted to receive the terminus of an exhaust tubulation 22 formed at the end 24 of the neck 26 of cathode ray tube 12.
  • the outside circumference of crown 18 has a diameter C equal to the diameter of the inside edges of the tube pin receiving apertures 16; thus, when base 10 is in position on the neck 26, the inside edges of the tube pins 28 ride on the outside circumference of crown 18 (see FIG. 2).
  • Crown 18 is also provided with a plurality of radially extending fins 30 which are located between the apertures 16 forming pockets therefor and adding further arcing protection.
  • the base 10 further includes an electrically insulating soft washer 32 of a suitable material such as sponge rubber or silicone rubber.
  • Washer 32 contains a plurality of apertures 34 matching in number and location the tube pin receiving apertures 16.
  • the diameter of the apertures 34 is larger than the diameter of the tube pins 28 and closely matches the diameter of glass nubbins 36 formed at the base of pins 28. It has been found necessary for the stated purpose of arc prevention for the diameter of the apertures 34 to closely match that of glass nubbins 38 to eliminate air gaps. When excessively smaller or larger apertures are employed the desired seal is imperfect and arcing will result.
  • washer 32 is variable within about 0.010 inch to 0.050 inch, it has been found that 0.040 inch is preferred. It is also preferred that the internal height of wall 15 is 0.010 inch to 0.020 inch less than that of washer 32 so that the washer is substantially enclosed and extends above wall 15 so that the washer can be placed in compression.
  • a suitable adhesive such as rubber cement or an RTV is used to adhere the washer 32 to base 10 and the entire assembly to neck 26.

Abstract

A base for a cathode ray tube includes a rubber washer having apertures of a size to fix over the glass nubbins surrounding the bottom of the tube pins where they exit from the neck of the tube. The base also includes a walled rim which contains the washer.

Description

BACKGROUND OF THE INVENTION
This invention relates to tube bases and more particularly to tube bases for cathode ray tubes which employ high voltage differentials between various tube pins.
Current and projected types of cathode ray tubes, particularly those employed in color television, have a small diameter neck containing the electron gun or guns. The necessary operating voltages for the various elements of these guns (heaters, cathodes, grids, focusing electrodes, etc.) are supplied via tube pins which are sealed into the end of the tube. As higher voltage guns have developed and the neck diameter has gotten smaller, decreasing from 36 mm to 29 mm, it has dictated that the tube pins, which are annularly arrayed thereabout, keep getting closer together.
Prior art tubes have always had large voltage differentials, sometimes on the order of 5 KV to 8 KV between various tube pins. Furthermore, if an arc originates between the anode and focus grid, the focus grid momentarily assumes anode potential (up to 30 KV) and this voltage can progress to the tube pins resulting in arcing from the focus pin to an adjacent pin, often damaging cathode emission. This subsequent arcing often occurs in the restricted area between the plastic base and the glass stem of the cathode ray tube. The intense heat developed by the arc results in a condition called "tracking"; a breakdown of the plastic base into a carbonaceous residue between the arcing pins, which results in a subsequent low insulation resistance.
Previously, it was attempted to control this arcing by surrounding a high voltage tube pin with an RTV; i.e., a room temperature vulcanizing silicone rubber. However, this process is difficult to control and required a trained operator. Additionally these high voltage connections have usually had some form of arc protection incorporated into the female socket, see, for example, U.S. Pat. Nos. 3,466,491 and 3,466,492. Such protection however, has proven incapable of providing adequate protection for the newer tube types.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to obviate the disadvantages of the prior art.
It is another object of the invention to enhance voltage protection in cathode ray tubes.
Yet another object of the invention is to prevent or alleviate inter-pin arcing in cathode ray tubes.
Yet another object of the invention is the provision of a tube base which includes arcing protection.
These objects are accomplished in one aspect of the invention by the provision of a base for a cathode ray tube which includes an electrically insulating washer confined within a walled rim of a plastic base. Provision is made therein for the projection therethrough of the tube pins. The compressible washer fills the voids between tube pins at the glass-base interface and provides an effective arcing deterent.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a base in accordance with an embodiment of the invention; and
FIG. 2 is an elevational view of a base and CRT neck, with some parts in section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For a better understanding of the present invention, together with other and further objects, advantages, and capabilities thereof reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings.
Referring now to the drawings with greater particularity there is shown in FIG. 1 a base 10 for a cathode ray tube 12. The base 10 comprises a circular rim 14 surrounded by a circumferential wall 15 having an outer diameter A and an inner diameter B. A plurality of tube pin receiving apertures 16 extend through the rim 14 and are spaced inwardly from the inner circumference of wall 15 in an annular array.
A hollow, substantially centrally located crown 18 is positioned on rim 14 and extends rearwardly therefrom, the internal portion 20 thereof being adapted to receive the terminus of an exhaust tubulation 22 formed at the end 24 of the neck 26 of cathode ray tube 12. The outside circumference of crown 18 has a diameter C equal to the diameter of the inside edges of the tube pin receiving apertures 16; thus, when base 10 is in position on the neck 26, the inside edges of the tube pins 28 ride on the outside circumference of crown 18 (see FIG. 2).
Crown 18 is also provided with a plurality of radially extending fins 30 which are located between the apertures 16 forming pockets therefor and adding further arcing protection.
The base 10 further includes an electrically insulating soft washer 32 of a suitable material such as sponge rubber or silicone rubber. Washer 32 contains a plurality of apertures 34 matching in number and location the tube pin receiving apertures 16. The diameter of the apertures 34 is larger than the diameter of the tube pins 28 and closely matches the diameter of glass nubbins 36 formed at the base of pins 28. It has been found necessary for the stated purpose of arc prevention for the diameter of the apertures 34 to closely match that of glass nubbins 38 to eliminate air gaps. When excessively smaller or larger apertures are employed the desired seal is imperfect and arcing will result.
While the thickness of washer 32 is variable within about 0.010 inch to 0.050 inch, it has been found that 0.040 inch is preferred. It is also preferred that the internal height of wall 15 is 0.010 inch to 0.020 inch less than that of washer 32 so that the washer is substantially enclosed and extends above wall 15 so that the washer can be placed in compression.
A suitable adhesive, such as rubber cement or an RTV is used to adhere the washer 32 to base 10 and the entire assembly to neck 26.
It will be seen from the above that there is herein provided a new and novel form of arc protection incorporated in a tube base.
While there has been shown and described what is at present considered to be the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims (3)

What is claimed is:
1. In combination, a cathode ray tube and a base therefor, said cathode ray tube having a cylindrical terminal portion closed by a substantially planar wall provided with a plurality of annularly arrayed, spaced, projecting tube pins each surrounded by a raised circumferential nubbin with a diameter larger than said pins where said pins exit from said wall, said base comprising: a circular rim having a given diameter surrounded by a peripheral wall having a given internal wall height; a plurality of tube pin receiving apertures extending through said rim, said apertures being spaced inwardly from the inner circumference of said peripheral wall and being annularly arrayed; a hollow, substantially centrally located crown positioned on said rim on a side opposite said peripheral wall and projecting therefrom, the internal portion of said crown being adapted to receive the terminus of an exhaust tubulation, the outside circumference of said crown having a diameter equal to the diameter of the inside edges of said tube pin receiving apertures and being further provided with a plurality of radially extending fins, said fins being located between said apertures; and an electrically insulating, soft washer fitted within said peripheral wall, said washer having a thickness greater than the internal height of said peripheral wall and being further provided with a plurality of apertures matching in number and location said tube pin receiving apertures in said rim, said apertures having a diameter closely matching the diameter of said nubbins.
2. The combination of claim 1 wherein said thickness of said washer exceeds the height of said peripheral wall by about 0.010 inch and 0.020 inch.
3. The base of claim 2 wherein said washer is formed from sponge rubber or silicone rubber.
US05/702,096 1976-07-02 1976-07-02 Cathode ray tube base Expired - Lifetime US4040708A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4076366A (en) * 1977-05-18 1978-02-28 Rca Corporation High voltage electron tube base with separate dielectric fill-hole
US4127313A (en) * 1977-05-18 1978-11-28 Rca Corporation High voltage electron tube base with drip relief means
US4155616A (en) * 1978-03-17 1979-05-22 Gte Sylvania Incorporated Cathode ray tube base
US4217014A (en) * 1979-01-31 1980-08-12 Rca Corporation Method for assembling a base to an electron tube
US4620764A (en) * 1985-07-11 1986-11-04 Rca Corporation Pin biasing base for electron tubes
US4674821A (en) * 1986-02-28 1987-06-23 Rca Corporation Electron tube base
GB2282004A (en) * 1993-09-21 1995-03-22 Sony Corp An insulator, e.g. for the terminals of a CRT
FR2745420A1 (en) * 1996-02-24 1997-08-29 Samsung Display Devices Co Ltd DEVICE FOR PROTECTING THE CONNECTION PIN OF A TUBE WITH CATHODE RAYS
US5818155A (en) * 1994-09-13 1998-10-06 Hitachi, Ltd. Cathode ray tube having a small-diameter neck and method of manufacture thereof
US6356015B2 (en) 1999-01-21 2002-03-12 Imaging & Sensing Technology Corporation Getter flash shield

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1850559A (en) * 1928-04-21 1932-03-22 Corning Glass Works Vacuum tube and mounting
US2659061A (en) * 1952-08-07 1953-11-10 Frank D Mirabella Adapter for miniature tubes
US3867671A (en) * 1973-11-19 1975-02-18 Amp Inc Spark gap protective device for cathode ray tubes
US3958854A (en) * 1974-10-02 1976-05-25 Gte Sylvania Incorporated Spark gap apparatus
US3979157A (en) * 1974-10-10 1976-09-07 Rca Corporation Electron tube base

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1850559A (en) * 1928-04-21 1932-03-22 Corning Glass Works Vacuum tube and mounting
US2659061A (en) * 1952-08-07 1953-11-10 Frank D Mirabella Adapter for miniature tubes
US3867671A (en) * 1973-11-19 1975-02-18 Amp Inc Spark gap protective device for cathode ray tubes
US3958854A (en) * 1974-10-02 1976-05-25 Gte Sylvania Incorporated Spark gap apparatus
US3979157A (en) * 1974-10-10 1976-09-07 Rca Corporation Electron tube base

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4076366A (en) * 1977-05-18 1978-02-28 Rca Corporation High voltage electron tube base with separate dielectric fill-hole
US4127313A (en) * 1977-05-18 1978-11-28 Rca Corporation High voltage electron tube base with drip relief means
US4155616A (en) * 1978-03-17 1979-05-22 Gte Sylvania Incorporated Cathode ray tube base
US4217014A (en) * 1979-01-31 1980-08-12 Rca Corporation Method for assembling a base to an electron tube
US4620764A (en) * 1985-07-11 1986-11-04 Rca Corporation Pin biasing base for electron tubes
US4674821A (en) * 1986-02-28 1987-06-23 Rca Corporation Electron tube base
GB2282004A (en) * 1993-09-21 1995-03-22 Sony Corp An insulator, e.g. for the terminals of a CRT
GB2282004B (en) * 1993-09-21 1997-06-25 Sony Corp An electric insulator and method of use thereof
US5990610A (en) * 1993-09-21 1999-11-23 Sony Corporation Manufacturing method and apparatus for insulating member
US6186851B1 (en) 1993-09-21 2001-02-13 Sony Corporation Manufacturing method and apparatus for insulating member
US5818155A (en) * 1994-09-13 1998-10-06 Hitachi, Ltd. Cathode ray tube having a small-diameter neck and method of manufacture thereof
US6246161B1 (en) 1994-09-13 2001-06-12 Hitachi, Ltd. Cathode ray tube having a small-diameter neck and method of manufacture thereof
FR2745420A1 (en) * 1996-02-24 1997-08-29 Samsung Display Devices Co Ltd DEVICE FOR PROTECTING THE CONNECTION PIN OF A TUBE WITH CATHODE RAYS
ES2126502A1 (en) * 1996-02-24 1999-03-16 Samsung Display Devices Co Ltd Protector for CRT lead pin
US6356015B2 (en) 1999-01-21 2002-03-12 Imaging & Sensing Technology Corporation Getter flash shield

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Owner name: NORTH AMERICAN PHILIPS CONSUMER ELECTRONICS CORP.

Free format text: ASSIGNS ITS ENTIRE RIGHT TITLE AND INTEREST, UNDER SAID PATENTS AND APPLICATIONS, SUBJECT TO CONDITIONS AND LICENSES EXISTING AS OF JANUARY 21, 1981.;ASSIGNOR:GTE PRODUCTS CORPORATION A DE CORP.;REEL/FRAME:003992/0284

Effective date: 19810708

Owner name: NORTH AMERICAN PHILIPS CONSUMER ELECTRONICS CORP.,

Free format text: ASSIGNS ITS ENTIRE RIGHT TITLE AND INTEREST, UNDER SAID PATENTS AND APPLICATIONS, SUBJECT TO CONDITIONS AND LICENSES EXISTING AS OF JANUARY 21, 1981.;ASSIGNOR:GTE PRODUCTS CORPORATION A DE CORP.;REEL/FRAME:003992/0284

Effective date: 19810708